This invention relates in general to the field of blinds and other vertically hung coverings or screens which can be raised by pulling down on a set (one or more) of lift cords, e.g., Venetian blinds and any other vertically hung coverings raised and lowered in similar fashion, and more particularly to such incorporating a pump-action xe2x80x9cwandxe2x80x9d for safely containing the control end(s) of the set of lift cords and for operating the same.
As used herein and in the claims appended hereto, the terms xe2x80x9cblindxe2x80x9d or xe2x80x9cblindsxe2x80x9d shall refer to any types or configurations of blinds which can be raised or foreshortened, wholly or in part, by pulling on a set of cords, and to any other vertically hung coverings or screens which can be raised in similar fashion.
This invention can be used to particular advantage on horizontal blinds, e.g., Venetian blinds. Conventionally, the raising and lowering of horizontal blinds have been controlled by one or more xe2x80x9cliftxe2x80x9d cords attached at their remote ends to a base rail of the blinds and strung through vertically aligned holes in the slats to a headrail in which they are strung around pulleys or rollers and through the headrail and ultimately down through a headrail cord lock where their control ends are left dangling. (As used herein, xe2x80x9cheadrailxe2x80x9d includes in general any structure at the top of a blind containing cord redirecting elements, e.g., pulleys and rollers, and which conventionally contain cord locking mechanisms.) Pulling down on the lift cords causes the base rail to be pulled up to a level corresponding to the amount that the lift cords were vertically displaced downward. As the base rail is pulled up, slats encountered by the base rail collapse against it. Releasing the lift cords allows gravity to act on the base rail and the collapsed slats, dropping the base rail to its lowest level, or to a desired lower level depending on the extent to which the lift cords have been released. Conventionally the base rail is secured at a desired level by locking the lift cords in place, and this is conventionally done by a cord lock mechanism in the head rail, which mechanism is engaged and released by tugging the lift cords at an angle from the vertical.
The above-described conventional blind control is widely used throughout the world, but nevertheless presents a safety problem. The problem is that infants and small children can become entangled in the dangling lift cords, too often resulting in death or injury from strangulation or as a result of restricted blood flow. This danger has resulted in the development of devices for making the loose lift cords inaccessible to such potential victims by controlling or enclosing the cords. However, the result has been that such safety devices are hard to operate, require additional steps, the use of both hands or, as in the case of such motorized devices, are relatively expensive. There is therefore a need for a blind control device that can eliminate the danger of loose, dangling cords but nevertheless be relatively inexpensive and easily operable.
The blind control wand of this invention provides a means for easily controlling the vertical position of blinds, is inexpensive, and safely controls the lift cords so there is no danger of loose dangling cords. Other advantages and attributes of this invention will be readily discernable upon a reading of the text hereinafter.
An object of this invention is to provide a means for safely controlling the vertical position of a blind.
Another object of this invention is to provide a means for easily and inexpensively controlling the vertical level of a blind.
Another object of this invention is to provide a means for easily and inexpensively controlling the vertical level of a blind without freely dangling cords.
Another object of this invention is to provide for a vertical covering which can be raised, partially or completely, by pulling down, in opposition to gravity, on a set of lift cords egressing from a headrail, a device for safely confining and operating the set of lift cords.
These objects, and other objects expressed or implied in this document, are accomplished by: (1) a first cord locking mechanism, disposed in the headrail, which when not released prevents the set of lift cords from moving axially upward, the first cord locking mechanism being releasable by selective manipulation of the set of lift cords; (2) an inner elongated tube pivotally affixed to the headrail, an operative length of the set of lift cords being disposed within the inner tube; (3) a tensioner for preventing slack in the set of lift cords; (4) an outer elongated tube telescopingly slidable over a range along the length of the inner tube; and (5) a second cord locking mechanism disposed within the inner tube but affixed to outer tube, the second cord locking mechanism when not released preventing the set of lift cords from moving axially upward relative to the outer tube, the second cord locking mechanism being released to allow free movement of the set of lift cords through it and the inner tube in response to selective manipulation of the outer tube. According to this invention a covering is raised by reciprocal (up and down) movement of the outer tube relative to the inner tube a selected number of times depending on how high the covering is to be raised, and it is lowered by simultaneously releasing both locking mechanisms. Preferably the first cord locking mechanism is released by simultaneously angling the tubes laterally from the vertical and momentarily pulling down on the outer tube. The tensioner can be an accumulator which accumulates slack in the lift cords when the blinds are being raised, and which discharges slack when the blinds are being lowered. A preferable embodiment of an accumulator is a spooler which spools the set when the covering is being raised according to the amount that the covering is being raised, and which unspools the set when the covering is being lowered according to the amount that the covering is being lowered. Preferably the tensioner is a closed loop of cord to which the set of lift cords is connected, the loop being rotatable in a first direction to take up slack in the set when the covering is being raised, and the set being rotatable in the opposite direction to allow the set to move up when the covering is being lowered. In the preferred embodiment, the loop is rotated in the first direction by being grasped by the second cord locking mechanism whenever the outer tube is pulled down, and wherein the loop is rotated in the opposite direction by pull of the set of lift cords whenever the set of lift cords are moving up due to being released from both locking mechanisms; and the closed loop of cord is wound around two rollersxe2x80x94preferably one journaled in the headrail as part of the headrail cord lock, and the other journaled in the inner tube. Preferably the second cord locking mechanism is released for a time whenever the outer tube is pushed to and held, for said time, at an upper limit of its sliding range, and further includes a control arm having at least a cord locked position and a cord released position, and a bias urging the control arm toward its cord locked position; and the inner tube further comprises a projection disposed at the upper limit of the outer tube""s sliding range, the control arm being forced by reaction to the projection to its cord released position whenever the outer tube is at the upper limit of its sliding range. Preferably the first cord locking mechanism includes a housing; a roller journaled in the housing; a serrated cylinder juxtaposed with roller, the set of lifts cord passing between the roller and the cylinder and wrapping partially around the roller, the cylinder having a range of radial movement between a rest position and a cord-locked position at which the set of lift cords is wedged between the cylinder and the roller; and a rack angled toward the roller and disposed within the cylinder""s range of movement, vertically upward axial movement of the set of lift cords tangentially dragging the cylinder from its rest position toward the rack which in turn guides the dragged cylinder to its cord-locked position. Preferably the second cord locking mechanism includes a body defining an upwardly narrowing, vertically oriented channel, the set of lift cords passing through the channel; an obstruction disposed in the channel, the set of lift cords passing around the obstruction, the obstruction being too large to pass through the narrowed channel when the cords are also in the channel; a bias for urging the obstruction upward in the channel to wedge the cords between the obstruction and the narrowed channel walls, the cords being axially slippable by the obstruction whenever the body is moving upward relative to the cords; and a release lever selectively operable against the bias to push the obstruction low enough in the channel to release the cords while the lever is being operated.